Telecommunications networks are typically conceptualized as having layered functionalities. The physical layer comprises a network of switches and cables (e.g., trunk lines) which are employed to connect devices (e.g., telephones) involved in a call (e.g., a “connection”). The connection layer is an abstraction that comprises a model of the physical network. Connection handling (which is performed over the connection layer) relates to the set up and release of connections and to the control of the physical telecommunications network. The call layer is involved in service handling, which includes service control, service execution, service signaling, service installation, service modification, and service administration. Within each layer information is transferred over signaling entities within the layer.
In some telecommunication systems, the call layer information and the connection layer information is signaled and routed along the same path from a call origin to a call destination. In such case, the resources needed for the call establishment are reserved hop by hop (e.g., as the information is signaled and routed from switch to switch through the physical network). As the call layer and connection layer are therefore closely coupled to each other, the binding between the call layer and the connection layer is resolved in runtime.
Modern telecommunication networks usually have the call layer and the connection layer separated from one another. As a consequence of the separation of the call layer and the connection layer, different networks are used for the call establishment and the connection establishment. The two networks (the call layer network and the connection layer network) usually have different topologies.
In operation, in setting up a call usually a call layer connection is initially established over the call layer network between two devices. Typically establishing the call layer connection involves exchange of control information that does not need any user plane (e.g., physical layer) connection. Subsequently, when a user plane connection is needed over the physical layer, a connection is established in the connection layer.
The two connections—the call layer connection and the connection layer connection—are routed from the same origin to the same destination. However, in view of the differing topologies of the call layer network and the connection layer network, the two connections do not have to be routed along the same path. The advantage of separate routing of the call layer connection and the connection layer connection is that resources for the user plane connection are only reserved and used when needed. Examples of call and connection separated telecommunications networks are provided in the following, all of which are incorporated herein by reference in their entirety: Swedish Patent Application 9601605-0, filed Apr. 26, 1996; U.S. Pat. No. 5,809,129; and, U.S. Pat. No. 5,710,882.
The separation of the call layer and the connection layer does, however, require some type of mechanism to bind the two layers to each other at certain nodes where the two layers meet. The signaling protocol of each layer needs to carry the binding mechanism, e.g., binding information. Typically, existing networks with existing protocols are used, and the binding information must be fit into already defined information entities within those protocols.
In the above regard, both in a core network and in a radio access network, the call layer generally uses a signaling system No. 7 (SS7) network or a TCP/IP network for call control signaling. On top of the SS7 or the TCP/IP protocol stacks there is an application protocol, such as RNSAP or RANAP. The RNSAP and RANAP protocols are used end-to-end in the network. Application specific resources, such as diversity handover units (DHOs) and codecs (coders/decoders) are handled and reserved at the call layer.
The present invention provides various binding information techniques when the call and the connection layers are separated in a telecommunications network. In a first embodiment of the invention, binding information is associated with connection endpoint information for a first connection end point at a first end node of the network. The connection endpoint information for the first connection end point can be vendor specific for a physical layer entity at the first end node, and may take the form of a concatenation of one or more of a node identifier, a hardware cabinet rack, a hardware slot, a hardware port, and a resource. The binding information and an ATM end system address (AESA) of the first end node are transmitted through the call layer to a second end node of the network. A second connection end point is reserved at the second end node, and a connection request is sent from the call layer to the connection layer. The connection request includes the binding information and the AESA of the first end node. Connection layer signaling which includes both the binding information and the AESA of the first end node is routed through the connection layer to the first end node. At the first end node, the binding information included in the connection layer signaling is used to obtain the connection endpoint information for the first connection end point. The connection layer then sends appropriate signals to through connect a switch in the physical layer of the first end node in accordance with the connection endpoint information for the first connection endpoint.
In one mode of the first embodiment, the binding information can be obtained by the call layer from a conversion table handled by the connection layer. The conversion table translates binding information and connection end point information. In another mode of the first embodiment, the conversion table is handled by the call layer. In this second mode of the first embodiment, upon receipt of the connection layer signaling at the first end node the binding information is sent to the call layer. The call layer obtains the connection endpoint information for the first connection endpoint from the conversion table in the call layer, and orders the connection layer to through connect the switch in the physical layer of the first end node in accordance with the connection endpoint information for the first connection endpoint.
In a second embodiment, an ATM end system address (AESA) is associated with a first connection end point at the first end node, and that ATM end system address (AESA) is transmitted in the call layer to the second end node whereat a second connection end point is reserved. A connection request is sent from the call layer to the connection layer, and connection layer signaling is routed through the connection layer to the first end node using the ATM end system address (AESA) associated with a first connection end point. The connection layer signaling includes the ATM end system address (AESA) associated with a first connection end point. Upon receipt of the connection layer signaling at the first end node, the first end node uses the ATM end system address (AESA) associated with a first connection end point to through connect the ATM switch in the physical layer to the first connection endpoint.
In a third embodiment, a dynamic routing number is associated both with a first end node of the network and with a first connection end point at the first end node. The dynamic routing number is preferably a dynamic AESA. Since the dynamic routing number (e.g., AESA) is reusable for association with other connection end points at the first end node, a table maintained at the first end node keeps track for which end point the dynamic routing number is currently used. The dynamic routing number is transmitted in the call layer to the second end node of the network. A second connection end point is reserved at the second end node, and a connection request is sent from the call layer to the connection layer. The connection request includes the dynamic routing number. Using the dynamic routing number included therein, connection layer signaling is routed through the connection layer from the second end node to the first end node. At the first end node, the dynamic routing number included in the connection layer signaling is used to obtain the first connection end point. The switch in the physical layer of the first end node is through connected in accordance with the first connection endpoint currently associated with the dynamic routing number.
In a fourth embodiment, connection endpoint information for a first connection end point of a first end node of the network is included in a vacant or otherwise unused field in an ATM end system address (AESA) of the first end node. The AESA of the first end node is transmitted in the call layer to a second end node of the network. A second connection end point is reserved at the second end node. A connection request is sent from the call layer to the connection layer. The connection request includes the AESA of the first end node. Connection layer signaling (which also includes the AESA of the first end node) is routed through the connection layer to the first end node. At the first end node, the connection endpoint information for the first connection end point of the first end node (included in the AESA of the first end node) is used to through connect the ATM switch in the physical layer to the first connection endpoint.